In recent years, there has existed a growing demand for air supported structures of large size as relatively permanent installations. In order to meet the increased demand for such structures, a need has developed to design the structures with long-term structural integrity and weather resistance.
In order to achieve structural integrity, an air supported structure generally must be designed to withstand two primary types of loading. The first is static and uniform loading that is produced by inflation pressure within the air supported structure. This is typically generated from the input of air from one or more blower systems. The systems are adapted to discharge air into the interior of the air supported structure. The second is generally asymmetric loading produced by air flow over the exterior of the structure. This is often referred to as aerodynamic loading. Depending on the wind speed and direction, aerodynamic loading is quite variable. In fact, under certain storm conditions, aerodynamic loading may change significantly in a very short period of time. Such rapid and drastic changes may affect the stability of the structure.
There are, of course, also various other asymmetric load factors to be considered. Heavy snowfall is one example of this type of load factor. However, in the absence of extreme loading from snow or another such asymmetric load factor, an air supported structure designed to withstand expected wind velocities for its location would normally withstand such other load factors. Accordingly, the ability to withstand aerodynamic loading is the key design feature in air supported structures.
Aerodynamic loading varies as the square of the exterior wind velocity and is proportionately much larger than the normal stresses due to inflation pressure alone. Additionally, it should be appreciated that inflation pressure static loading and variable aerodynamic loading are additive. They also almost invariably act in the same direction.
When any non-uniform loading occurs, equilibrium conditions in the air supported structure may only be achieved either by redistribution of the load or by distortion of the structure. Of course, distortion of the structure is undesirable. Hence, it is critically important for the air supported structure to be designed to provide effective redistribution of load factors. The present invention meets this need by providing improved redistribution and load balancing capabilities.